Fixed: Converter was copying too much state from Nib2Cib, framework resources could not be referenced in Xcode.

* State *
Previously the Converter class needlessly copied a whole bunch of state from the Nib2Cib class, which was not only poor factoring, but made for easy omissions of state when instantiating a new Converter, such as was done in NSNib.j.

This commit pushes all state not specific to Converter up to Nib2Cib. This allowed removal of redundant code in NSNib -NS_initWithCoder.

* Resources *
Previously it was not possible to use custom images that were located in a framework, because only the app's Resources directory was searched.

This commit automatically searches all frameworks for Resources directories. When a custom image is specified in Xcode, first the app's Resources directory is searched, then all framework Resource directories. Alternately, the specific framework to use can be specified in Xcode by using the form framework@image.

At runtime, the framework is loaded by its identifier (as specified in Info.plist), and if there is no identifier, by searching next to the current AppKit framework.

All of this renders the nib2cib -R option completely obsolete, so it was removed from the NibApplication/Jakefile template.